Summary of the method to determine whether a string is a number

This article summarizes the method of java to determine whether a string is a number. Share it for your reference, as follows:

Method 1: Use the functions that come with JAVA

 public static boolean isNumeric(String str){ for (int i = str.length();--i>=0;){ if (!Character.isDigit(str.charAt(i))){ return false; } } return true;}

Method 2: Use regular expressions

 public static boolean isNumeric(String str){ Pattern pattern = Pattern.compile("[0-9]*"); return pattern.matcher(str).matches(); }

Method 3: Use ascii code

 public static boolean isNumeric(String str){ for(int i=str.length();--i>=0;){ int chr=str.charAt(i); if(chr<48 || chr>57) return false; } return true;}

I hope this article will be helpful to everyone's Java programming.